Oilpan: move 2D Canvas and WebGL objects to the heap.

Source/core/html/canvas/WebGLRenderingContext.cpp

Index: Source/core/html/canvas/WebGLRenderingContext.cpp
diff --git a/Source/core/html/canvas/WebGLRenderingContext.cpp b/Source/core/html/canvas/WebGLRenderingContext.cpp
index 1e34b4523b365c8e796077190d88663fb8ef3869..1411a90f60f373b915f1d5b9bccd663b100e184c 100644
--- a/Source/core/html/canvas/WebGLRenderingContext.cpp
+++ b/Source/core/html/canvas/WebGLRenderingContext.cpp
@@ -79,7 +79,7 @@ PassOwnPtrWillBeRawPtr<WebGLRenderingContext> WebGLRenderingContext::create(HTML
     }
 
     // The only situation that attrs is null is through Document::getCSSCanvasContext().
-    RefPtr<WebGLContextAttributes> defaultAttrs;
+    RefPtrWillBeRawPtr<WebGLContextAttributes> defaultAttrs = nullptr;
     if (!attrs) {
         defaultAttrs = WebGLContextAttributes::create();
         attrs = defaultAttrs.get();
@@ -148,4 +148,30 @@ void WebGLRenderingContext::registerContextExtensions()
     registerExtension<WebGLLoseContext>(m_webglLoseContext, ApprovedExtension, bothPrefixes);
 }
 
+void WebGLRenderingContext::trace(Visitor* visitor)
+{
+    visitor->trace(m_angleInstancedArrays);
+    visitor->trace(m_extBlendMinMax);
+    visitor->trace(m_extFragDepth);
+    visitor->trace(m_extShaderTextureLOD);
+    visitor->trace(m_extTextureFilterAnisotropic);
+    visitor->trace(m_oesTextureFloat);
+    visitor->trace(m_oesTextureFloatLinear);
+    visitor->trace(m_oesTextureHalfFloat);
+    visitor->trace(m_oesTextureHalfFloatLinear);
+    visitor->trace(m_oesStandardDerivatives);
+    visitor->trace(m_oesVertexArrayObject);
+    visitor->trace(m_oesElementIndexUint);
+    visitor->trace(m_webglLoseContext);
+    visitor->trace(m_webglDebugRendererInfo);
+    visitor->trace(m_webglDebugShaders);
+    visitor->trace(m_webglDrawBuffers);
+    visitor->trace(m_webglCompressedTextureATC);
+    visitor->trace(m_webglCompressedTextureETC1);
+    visitor->trace(m_webglCompressedTexturePVRTC);
+    visitor->trace(m_webglCompressedTextureS3TC);
+    visitor->trace(m_webglDepthTexture);
+    WebGLRenderingContextBase::trace(visitor);
+}
+
 } // namespace WebCore